What, and how much fish should we be eating?

Fish Facts

By Melinda McGarty Webb/HealthyLife

Photo: GettyImages/Dwight Eschliman

We’ve all heard that eating fish is good for us. It’s widely considered a great source of protein that’s relatively low in saturated fat and calories, packed with omega-3 fatty acids to help your heart and brain. Many types of fish also are great sources of vitamins D and B12, iron, zinc, phosphorus and a laundry list of other nutrients.

But standing at the seafood counter at the local market can be confusing. We’re told to consider a fish’s mercury content, as well as whether it’s sustainably caught. Who can keep track of the mental juggling and still plan a decent meal based on the day’s catch?

In general, bigger predatory fish have higher mercury content. In fact, the EPA and FDA warn against eating shark, swordfish, King Mackerel, or tilefish because they contain high levels of mercury. That joint recommendation further suggests people eat up to 12 ounces per week (about two average meals) of fish and shellfish that are lower in mercury, including shrimp, canned light tuna, salmon, pollock and catfish.

Photo: GettyImages/Thomas Barwick

And no, mercury found in fish isn’t the same type of mercury used in thermometers or compact fluorescent bulbs. Instead, it’s methylmercury, a neurotoxin that accumulates more quickly in our bodies and takes longer to be eliminated than elemental mercury. In high doses, methylmercury can be particularly harmful to the developing nervous systems of young children and unborn babies. And cooking doesn’t reduce mercury levels. It’s not like a bacteria that can be killed at high heat. If it’s in the fish, it remains there regardless of how you prepare it.

You can feed lower-mercury fish to a young child twice a week, but in smaller portions than the 12 ounces recommended for adults, say the FDA and EPA. Still, direct ingestion isn’t the only way our children can be exposed. Women can pass methylmercury to their babies during pregnancy, and nursing mothers can pass it through breast milk. What makes this even scarier is that methylmercury can accumulate in a woman’s blood stream before pregnancy and then be passed to her unborn child once she’s pregnant. That means it’s not enough to monitor your mercury consumption while you’re pregnant. If you are of childbearing age, you might want to be mindful of how much mercury you ingest. The body eventually removes it naturally, but it could take more than a year for levels to drop significantly, according to the FDA.

But don’t let that scare you off. “Fish is an excellent source of lean protein. It’s high in the good fats, and low in the bad fats,” says Jenny Ives, a clinical dietitian at Saratoga Hospital. “It decreases your risk for heart disease; fights inflammation in the heart and joints; is high in antioxidants; and rich in calcium, phosphorus, minerals, iron, zinc, potassium. … It’s also high in protein. Per one ounce of fish, you get seven grams of protein.” While chicken and beef are comparable in terms of protein, they are both higher in fat and cholesterol.

When many of us think of the health benefits of fish, we immediately think of omega-3 fatty acids. “They help decrease triglycerides and total cholesterol in the body, and have been shown to have an anti-inflammatory effect in the body — in the heart and surrounding the heart. And in people who have arthritis or osteoporosis, it can help relieve inflammation in the joint area… Studies have shown they also help athletes reduce stress post-exercise.”

Some still shy away from shellfish because they think these mollusks and crustaceans are high in cholesterol. But that’s not the case. “There are a few reasons why shellfish may have a bad reputation when it comes to cholesterol,” according to information from NYU Langone Medical Center in Manhattan. “First, shellfish contain a variety of sterols, a group of chemical compounds that includes cholesterol. Previously, scientists could not distinguish among the different sterols and all were labeled as cholesterol. As a result, the amount of cholesterol in shellfish was overestimated. In reality, shellfish contain less cholesterol than meat or poultry.”

Ellie Wilson, the New York State Dietetic Association’s media representative for the Albany area and the senior nutritionist for the Price Chopper supermarkets, expresses a similar sentiment. “We’ve been trained to believe cholesterol in foods is harmful, but what we now know is that it’s far less harmful than saturated and trans fats. … We really don’t look at the cholesterol in lobster and shrimp because there are still plenty of positives to those species. It’s really similar to eggs. Years ago, you used to hear very negative things about eggs and cholesterol. As time has marched on, though, science has determined that cholesterol itself was never really the problem. The positives outweigh the negatives.”

Now that doesn’t give you license to gorge on stuffed lobster with drawn butter, Coquilles St. Jacques and fried whole belly clams drenched in tartar sauce. It’s the manner in which shellfish is sometimes prepared that can be problematic. Instead, try steaming, boiling, grilling, broiling or baking your shellfish. Those methods all preserve its natural sweetness and don’t pack on the fat and calories.

When it comes to fish, these simple preparations can be very satisfying — and incredibly easy. “People should realize how easy seafood is to prepare,” Wilson says. “In today’s very busy lifestyles, people are looking for things to cook in a quick amount of time. There’s almost nothing faster from a protein point of view than seafood. This could be a 10-minute dinner… And it’s really amenable to adding different flavors to it. Some of my favorite things to do are add some of the great variety of no-salt seasonings that are out there now.”

In addition to not adding unnecessary fat and calories, broiling and baking certain fish may be beneficial for another reason, and it has to do with polychlorinated biphenyls, or PCBs. These toxins accumulate in the fat of fish, particularly in farmed salmon. “To reduce your exposure to PCBs [when eating farmed salmon], trim fat from fish before cooking. Also, choose broiling, baking or grilling over frying, as these cooking methods allow the PCB-laden fat to cook off the fish,” says the Environmental Working Group, a nonprofit environmental health research and advocacy organization, on its website. “When possible, choose wild and canned Alaskan salmon instead of farmed, and eat farmed salmon no more than once a month.”

The wild-caught versus farmed fish debate has been raging for years. In 2003, seven of 10 farmed salmon purchased at grocery stores in Washington, D.C., San Francisco, and Portland, Ore., were contaminated with PCBs at levels that raised health concerns, according to independent laboratory commissioned by the Environmental Working Group. (Disposal of PCBs into waterways contaminated rivers and oceans throughout the United States, until their manufacture and use was banned domestically in 1976.) Immediately, many consumers started questioning the source of their salmon. Was it caught in the wild, or was it raised on a farm?

Farmed salmon sometimes live in densely populated tanks or pens where diseases can spread rapidly. To keep these illnesses at bay, they’re often treated with antibiotics, and they’re fed fish meal containing color enhancers to give their flesh that salmony color. The fish accumulate PCBs not only from the water in which they swim, but also from this fish meal they’re fed, which consists largely of ground-up small fish. PCBs tend to accumulate in the fat of fish, and the meal is designed to be high in fish oil.

Our fish supply is not limitless. “Humans have been fishing the oceans for thousands of years. But over the past five decades technology has allowed us to fish farther, deeper and more efficiently than ever before. Scientists estimate that we have removed as much as 90 percent of the large predatory fish such as shark, swordfish and cod from the world’s oceans,” according to literature from the Monterey Bay Aquarium’s Seafood Watch program. Our oceans are in a state of “silent collapse,” they say, threatening our food supply, marine economies, recreation and the legacy we leave our children. “Through better practices, we can create healthy, abundant oceans for everyone.”

Prepare your fish, safely

Thawing Thaw frozen seafood gradually by placing it in the refrigerator overnight. If you have to thaw seafood quickly, either seal it in a plastic bag and immerse it in cold water or, if the food will be cooked immediately thereafter, microwave it on the “defrost” setting and stop the defrost cycle while the fish is still icy but pliable.

Cooking Most seafood should be cooked to an internal temperature of 145ºF. If you don’t have a food thermometer, there are other ways to determine whether seafood is done.

Fish

The flesh should be opaque and separate easily with a fork

Shrimp and Lobster

The flesh becomes pearly and opaque

Scallops

The flesh turns opaque and firm

Clams, Mussels, and Oysters

The shells open during cooking — throw out any that don’t open

Did You Know? Uncooked, spoiled seafood can have an ammonia odor that becomes stronger after cooking. If you smell an ammonia odor in raw or cooked seafood, do not eat it.

— Courtesy of the U. S. Food and Drug Administration

Photo: GettyImages/Juanmonino

Selecting fish

— how do I know if it’s fresh?

Follow these general guidelines for safely selecting fish, shrimp and shellfish.

Shellfish

1. Look for the label

Look for tags on sacks or containers of live shellfish (in the shell) and labels on containers or packages of shucked shellfish. These tags and labels contain specific information about the product, including the processor’s certification number. This means that the shellfish were harvested and processed in accordance with national shellfish safety controls.

2. Discard Cracked/Broken Ones

Throw away clams, oysters and mussels if their shells are cracked or broken.

3. Do a “Tap Test”

Live clams, oysters and mussels will close when the shell is tapped. If they don’t close when tapped, do not select them.

4. Check for Leg Movement

Live crabs and lobsters should show some leg movement. They spoil rapidly after death, so only live crabs and lobsters should be selected and prepared.

Fresh Fish and Shrimp

1. How it’s stored

Only buy fish that is refrigerated or displayed on a thick bed of fresh ice that is not melting (preferably in a case or under some type of cover.)

2. How it smells

Fish should smell fresh and mild, not fishy, sour or ammonia-like. Shrimp should have little or no odor.

Fish fillets should display no discoloration, darkening or drying around the edges.

Shrimp flesh should be translucent and shiny with little or no odor.

4. How it feels

The flesh should spring back when pressed.

5. Check the label

Some refrigerated seafood may have time/temperature indicators on their packaging, which show if the product has been stored at the proper temperature. Always check the indicators when they are present and only buy the seafood if the indicator shows that the
product is safe to eat.

— Courtesy U.S. Food and Drug Administration

Tuna — the old standby

For many people, canned tuna is a pantry staple — a quick, inexpensive sandwich, an easy way to add protein to a salad, or even a comforting casserole or pasta dish. But be wary of which type of tuna you choose. Canned light tuna is preferable to albacore (the white tuna) in terms of mercury contamination because the smaller light tuna is likely to have accumulated less. The FDA and EPA advise limiting intake of both albacore tuna and tuna steaks or fillets to up to six ounces, which is about one average meal, per week.

Not all fish are sustainably equal

Even if you know what type of fish to buy, there are situations when you should ask where and how the fish was caught. With haddock, for example, if it was caught in the United States with a hook and line, then it’s a great choice. Think twice if it comes from anywhere else or is trawled in the U.S. Tilapia farmed in the U.S. is the best because it’s farmed in an environmentally friendly and responsible manner. Tilapia farmed in Central or South America is still a good option, but if it comes from Asia, it’s listed by Seafood Watch as a fish to avoid because it’s being caught or farmed in ways “that harm other marine life or the environment.”